Such containers are used a containers for hydraulic media, for example with hydraulic steering systems. Here, they are used as reservoirs and compensation tanks for hydraulic media being conveyed by a servo pump to the steering system and being returned from there into the hydraulic medium container.
The cover can be connected with the container cup by different means. In connection with an oil container in accordance with DE-C2-31 41 728, the cover is held by means of a screw cap on a screw fastened to the container cup.
In another oil container in accordance with DE-C2-27 42 610, the cover has been directly screwed to the container cup.
At a more recent time it was proposed to connect the cover of a container for a hydraulic medium, wherein the cover can be bonded to the container cup, by bonding the cover with the container cup by means of an inertia welding process. However, in the course of applying this method it was found that, when containers for hydraulic media made of a plastic material are inertia-welded, it is possible that undesired particles of the plastic material, the so-called "lateral welding waste", are created on both sides of the weld seam, which can contaminate the container on the inside and the outside.
A holder or container made of a plastic material is known from NL-A-7 011 090, wherein two elements, which are to be connected, do not move in respect to each other, while a third, ring-shaped element rotates in relation to the two said elements and constitutes a connecting point with the two elements. By means of the method described in the document for connecting two elements which are cylindrical and/or circular in cross section while employing an inertia welding process, it is not possible to connect elements which do not have a dynamically balanced cross section.